Use of Larch Light Rings for an Evaluation of Volcanic Explosivity Index

Volcanic eruptions lead to a global short-term drop in air temperature, including a shortening of the growing season. A reaction to these short-term climatic changes is the formation of light rings (LRs) in Siberian larches growing in the Siberian Subarctic area. The relationships between mass formation (and spatial spread) of LRs and the Volcanic Explosivity Index (VEI) are shown based on an analysis of larch cores collected at 18 points in the northern forest–tundra from 67°32′ to 167°40′ N. The eruptions with VEI = 6 and higher statistically differ from weaker eruptions by the number of LRs and their spatial distribution. The doubtful dates of several strong eruptions are discussed.     

Temporal changes (1989–1999) in deep-sea metazoan meiofaunal assemblages on the Porcupine Abyssal Plain,NE Atlantic

Trends among major metazoan meiofaunal taxa were investigated based on 56 deployments of a multicorer at 10 time points over a period of 11 years (1989–1999) at the Porcupine Abyssal Plain Sustained Observatory site (PAP-SO: 48°50′N 16°30′W, 4850 m depth). This area is characterised by a strong seasonality in the deposition of organic matter to the seafloor and by the massive increase in the density of holothurian species since 1996, the so-called ‘Amperima event’. Total meiofaunal densities ranged from 346 to 1074 ind.×10 cm⁻² and showed a significant increase with time when time was represented by cruises, years and the ‘Amperima period’ (1996–1999) vs. the pre-Amperima period (1989–1994). This pattern was driven mainly by the nematodes, which were the dominant taxon (∼90% of total abundance). The third most abundant group, the polychaetes, also increased significantly in abundance over the time series, while the ostracods showed a significant decrease. Most other taxa, including the second-ranked group, the copepods (harpacticoids and nauplii), did not exhibit significant temporal changes in abundance. Ordination of taxon composition showed a shift from the pre-Amperima to the Amperima periods, a trend supported by the significant correlation between the x-ordinate and time. The majority (52–75%) of meiofaunal animals inhabited the top 2 cm of the 5 cm sediment cores analysed. There were significant increases in the proportion of total meiofauna, nematodes and copepods (but not polychaetes) inhabiting the 0–1 cm layer over time (represented by cruises) and between the pre-Amperima and Amperima periods in the case of copepods and polychaetes. During the intensively sampled period (1996–1997), there were indications of seasonal changes in the vertical distribution patterns of total meiofauna and nematodes within the sediment. We discuss the potential link between temporal variations in organic matter flux to the seafloor and meiofaunal populations, considering both qualitative and quantitative changes in fluxes and how they may be linked to climate variations.     

内蒙古准格尔旗树轮年表的建立及其气候意义

通过在内蒙古准格尔旗建立树轮宽度年表、早材宽度年表和晚材宽度年表，并和邻近呼和浩特气象站的资料进行相关分析，结果表明各年表和2—6月的降水量之和呈正相关关系。在准格尔旗西南方向、相距约500km的贺兰山树木生长主要受到5—7月降水量的支配。从这两个区域气象站资料的对比中发现，月降水量、月平均温度的多年平均值在年内表现出非常好的一致性，对应单月月降水量、月平均温度序列显著相关，反映了其受共同的气候驱动因子支配。从两个区域年表对各自气象站气候因子的响应可以看出，树木的生长都主要受到生长季前期和生长季早期降水量的支配。     

Coral extension rates in the NW Indian Ocean I: reconstruction of 20th century SST variability and monsoon current strength

To date, only a few coral proxy studies have investigated coral growth as an indicator of climate variability. This study presents the first extension-rate record (Porites lutea) from the Maldives (NW Indian Ocean), inferred from skeletal δ¹⁸O chronology for the lagoon of Rasdhoo Atoll (4°N/73°W) in the central area of the Maldives, influenced by the Indian monsoon. The record spans 90 years over the period 1917–2007. The mean annual extension over this period was 9.9 mm/year, and an increase of annual extension rates until 1990 by 3 mm/year can be explained by a rise of 0.7°C in sea surface temperature (SST) in this region. After 1990, the extension rates do no continue increasing, possibly due to ecological stress caused by progressive ocean warming and acidification. The correlation between annual extension rates and SSTs is thus significant and strong in the lower part of the record until 1955 (r = +0.69, p < 0.0001), but weaker thereafter (r = +0.44, p < 0.001). The extension rates yield a distinct interannual variability of 3–4 years, caused by interannual SST fluctuations driven by the El Ni?o-Southern Oscillation. A variability of 8–9 years is likely driven by SST variations endemic to the Indian Ocean. Spectral peaks between 18–19 years and 6–7 years cannot be explained by SST fluctuations, but by variations in the strength of the SW monsoon currents. It is suggested that during phases of stronger monsoon activity, the coral sacrificed coral extension in favor of a denser, more robust skeleton. The geomorphology of the atoll may strengthen the potential of this new coral archive to track climate variability.     

贺兰山过去196年降水的树轮宽度重建及降水变率

贺兰山属于中国北方的半干旱地区,位于东亚夏季风的西北缘。应用贺兰山南段、中段和北段的3组树轮宽度差值年表合成贺兰山树轮宽度年表,应用邻近采样点的贺兰山东坡、山顶和西坡的气象站资料合成贺兰山气象数据。通过贺兰山树轮宽度年表和贺兰山气象数据的线性回归分析,重建了1802—1997年2—7月降水标准化序列,重建方程的方差解释量是46%。计算重建序列的11年滑动平均标准差后,发现存在着3次标准差的突然变化:1908年标准差由前年的0.38增加到当年的0.56,1942年标准差由两年前的0.57增加到当年的0.70,1956年标准差由前年的0.74降低到当年的0.63。小波分析表明,1908年到1949年之间存在显著的11年准周期,1942年出现2年准周期,该2年准周期到1959年彻底消失。1965—1997年,存在由8年向3年过渡的准周期。11年周期对应着太阳活动周期,2年周期对应“准两年脉动”,8年到3年周期与ENSO周期比较一致。故此认为,当太阳活动、“准两年脉动”或ENSO活动增强时,贺兰山地区降水变率一般比较大,年际间降水变得不稳定。     

冬季北太平洋西部上层海洋的热量输送

用海气界面净热量收支和1950－1979年表层水温资料，计算了冬季北太平洋西部上层海洋热通量散度场，指出冬季北太平洋西部黑潮将大量低纬暖水输送到中高纬度海域，在30－35°N最大；亲潮将极地冷水沿千岛群岛向南输送，在45－50°N最大；两者在40°N附近相遇，混合减弱后沿纬向东传。同时用EOF分析方法对热通量散度距平场分型，前3个主要型分别为：黑潮亲潮偶合型、北太平洋海流型和冷平流优势型。最后还揭示了第一主要型与北太平洋副热带高压之间有意义的相关关系。     

A description of short period temperature fluctuations in the upper ocean

Dynamical properties of short-period temperature fluctuations are studied. Water temperature was measured continuously at several depths at the following stations: at 38°29.5′N, 141°35.8′E (100 m depth) on the continental shelf off Miyagi Prefecture in the summer of 1967, at 35°01.8′N, 139°0.8.5′E (100 m depth) in Sagami Bay in the summer of 1968, and at 32°32.2′N, 129°53.7′E (74 m depth) in Tachibana Bay in the summer of 1970. These measurements were made with a thermistor array laid down from the R. V.Tanseimaru (Ocean Research Institute, University of Tokyo) which was fixed with bow and stern anchors. Significant temperature fluctuations found at the first and the third stations are thought to be due to first mode internal waves having amplitude 3 to 5 m and period 5 to 20 minutes. The wave length of the waves is estimated to be 25 m to 400 m from the observed density structure. At the second station, we found second-mode internal waves. The period, amplitude and wave length of the waves are about 30 minutes, 1.3 m and 600 m, respectively. In all cases, the spectral density of the temperature fluctuations decreases with increase in frequency. However, the decrease obey neither the ?3 power law nor the ?5/3 power law. Coherences in the temperature fluctuations between two depths of measurement in the seasonal thermocline are significantly high in the range of frequencies lower than the local Brunt-Väisälä frequency, but are low in the higher frequency range. At the first and the third stations, the difference in the level of coherences between the lower frequencies and the higher frequencies are large. Phase differences between two depths in the thermocline are small in the lower frequency range. This suggests that the first-mode internal waves are predominant over higher-mode internal waves and over other disturbances.     

Ice Sheet-Thermohaline Circulation Interactions in a Climate Model of Intermediate Complexity

A vertically integrated dynamic ice sheet model is coupled to the atmosphere-ocean-sea ice-land surface climate model recently developed by Wang and Mysak (2000). The background lateral (east-west) ice sheet discharge rate used by Gallee et al. (1992) is reduced and the planetary emissivity is increased (to parameterize the cooling effect of a decrease of the atmospheric CO₂ concentration), in order to build up substantial ice sheets during a glacial period and hence set the stage for ice sheet-thermohaline circulation (THC) interactions. The following iceberg calving scheme is then introduced: when the maximum model height of the North American ice sheet reaches a critical value (2400 m), a prescribed lateral discharged rate is imposed on top of the background discharge rate for a finite time. Per a small prescribed discharge rate, repeated small iceberg calving events occur, which lead to millennial-scale climate cycles with small amplitudes. These are a crude representation of Dansgaard-Oeschger oscillations. Over one such cycle, the zonally averaged January surface air temperature (SAT) drops about 1.5°C at 72.5°N. However, a large prescribed lateral discharge rate leads to the shut down of the THC. In this case, the January SAT drops about 5°C at 72.5°N, the sea ice extent advances equatorward from 57.5° to 47.5°N and the net ice accumulation rate at the grid of maximum ice sheet height is reduced from 0.24 to 0.15 m/y. Since data strongly suggest that a collapsed THC was not a steady state during the last glacial, we restore the THC by increasing the vertical diffusivity in the North Atlantic Ocean for a finite time. The resulting climate cycles associated with conveyor-on and conveyor-off phases have much larger amplitudes; furthermore, the strong iceberg calving events lead to a larger loss of ice sheet mass and hence the period of the oscillations is longer (several thousand years). This revised version was published online in August 2006 with corrections to the Cover Date.     

Seasonal and inter-annual biogeochemical variations in the Porcupine Abyssal Plain 2003–2005 associated with winter mixing and surface circulation

We present a 3-year multidisciplinary biogeochemical data set taken in situ at the Porcupine Abyssal Plain (PAP) time-series observatory in the Northeast Atlantic (49°N, 16.5°W; water depth ∼4850 m) for the period 2003 to 2005. The high-resolution year-round autonomous measurements include temperature, salinity, chlorophyll-a (derived from in situ chlorophyll-fluorescence) and inorganic nitrate, all at a nominal depth of 30 m on an Eulerian observatory mooring. This study compares these in situ time-series data with satellite chlorophyll-a data, regional data from a ship of opportunity, mixed-layer depth measurements from profiling Argo floats and lateral advection estimates from altimetry. This combined and substantial data set is used to analyse seasonal and inter-annual variability in hydrography and nitrate concentrations in relation to convective mixing and lateral advection. The PAP observatory site is in the inter-gyre region of the North Atlantic where convective mixing ranges from 25 m in the summer to over 400 m in winter when nutrients are supplied to the surface. Small inter-annual changes in the winter mixed layer can result in large changes in nitrate supply and productivity. However the decrease in maximum winter nitrate over the three-year period, from 10 to 7 mmol m⁻³, cannot be fully explained by convective mixing. Trajectories leading to the PAP site, computed from altimetry-derived geostrophic velocities, confirm that lateral advection cannot be ignored at this site and may be an important process along with convective mixing. Over the three years, there is an associated decrease in new production calculated from nitrate assimilation from 85.4 to 40.3±4.3 gCm⁻² a⁻¹. This confirms year-to-year variability in primary production seen in model estimates for the region. The continuous in situ dataset also shows inter-annual variation in the timing of the spring bloom due to variations in heat flux; the 2005 bloom occurred earlier than in 2004.     

Transport of Antarctic Bottom Water through passages in the East Azores Ridge (37° N) in the East Atlantic

The structure of northerly overflow of Antarctic Bottom Water (AABW) through passages in the East Azores Ridge (37° N) in the East Atlantic from the Madeira Basin to the Iberian Basin is studied on the basis of hydrographic measurements carried out by the Institute of Oceanology, Russian Academy of Sciences (RAS) in October 2011, historical World Ocean Data Base 2009, and recent data on the bottom topography. The overflow of the coldest layers of this water occurs through two passages with close depths at 16° W (Discovery Gap) and at 19°30′ W (nameless Western Gap). It is shown that it is likely that the role of the latter passage in water transport was underestimated in earlier publications because the water (2.01°C) found in the region north of the Western Gap was cooler than in the region north of the Discovery Gap (2.03°C). In 2011, we found a decrease of 0.01°C in the AABW temperature near the bottom compared to previous measurements in 1982 (from 2.011°C to 2.002°C). Analysis of the historical database shows that this decrease is most likely caused by the cooling trend in the abyssal waters in the East Atlantic basins.     

Heat fluxes across 7°30′N and 4°30′S in the Atlantic Ocean

Heat fluxes are estimated across transatlantic sections made at 4°30′S and 7°30′N in January–March 1993, following Hall and Bryden (1982. Deep-Sea Research 29, 339–359). Particular care is given to the computation of Ekman volume and heat fluxes, which are assessed both (a) from the windstress data for the period of the cruise and (b) from the comparison between geostrophic and Vessel Mounted Acoustic Doppler Current Profiler (VM-ADCP) velocities. In contrast with previous studies, the two estimates for Ekman fluxes do not converge for either section: (a) (11.5±0.5 Sv; 1.01±0.05 PW) across 7°30′N and (−9.3±1.2 Sv; −0.85±0.12 PW) across 4°30′S when windstress data at the date of the hydrographic stations are used; (b) (6.3±1.1 Sv; 0.56±0.09 PW) across 7°30′N and (−3.4±3.0 Sv; −0.35±0.24 PW) across 4°30′N when the ageostrophic transport above the thermocline is used. The divergence would have been even greater at 4°30′S if the strong ageostrophic signal beneath the thermocline, which brings a transport of (8.4 Sv; 0.82 PW), had been considered. The corresponding total meridional heat fluxes are: (a) 1.40±0.16 PW and (b) 0.95±0.20 PW across 7°30′N, (a) 1.05±0.12 PW and (b) 1.67±0.14 PW (2.39±0.14 PW when the subthermocline ageostrophic transport is taken into account) across 4°30′S.The estimates based on windstress data are compared with the results from an inverse model (Lux and Mercier, 1999) to show the importance of the heat flux due to the deviation of the local depth-averaged potential temperature from its average over the section, which is neglected in the Hall and Bryden (1982. Deep-Sea Research 29, 339–359) method but is not negligible in our computation in which we do not isolate the transport of the western boundary current east of the 200 m isobath; this corrective flux amounts here to −0.19 PW across 7°30′N and 0.33 PW across 4°30′S.The seasonal variability of the meridional heat flux across 7°30′N is studied through the hydrographic data collected during the ETAMBOT 1–2 cruises, which repeated the 7°30′N section west of 35°W in September 1995 and April 1996. When the section is completed east of 35°W with CITHER 1 data and when windstress data are used for the computation of the Ekman transport, the estimates for the meridional heat fluxes are 0.20±0.14 PW in September 1995 and 1.69±0.27 PW in April 1996. The estimates fit well with results from numerical models.     

Analysis of volcanogenic perturbations of the subarctic ozonosphere on the basis of space monitoring data

The response of the total ozone (TO) at subarctic latitudes to volcanic eruptions, products of which were injected into the stratosphere, is analyzed. It is established that the behavior of the series of average annual TO values according to the TOMS, SCIAMACHY, and GOME space equipment data averaged for 55°–65° N latitudes agrees with the activity of explosive volcanic eruptions. The series of the TO satellite monitoring instrumental data are extended by 200 years into the past using a reconstruction from the dendro-chronologic data. An analysis of the series of TO reconstructed values indicates that volcanogenic perturbations of the subarctic ozonosphere initiate long-term negative TO deviations. In this case, the TO negative deviation depth depends on the frequency of the ozonosphere volcanogenic perturbations and the phase of quasiperiodic oscillation cycles rather than on the strength of a single volcanic explosion.     

Perceptions and attitudes of stakeholders towards the wildlife refuge of Ilha dos Lobos,a marine protected area in Brazil

At the north coast of Rio Grande do Sul state, southern Brazilian coast, the Wildlife Refuge of Ilha dos Lobos (29°20′S; 49°43′W), is a full protection area and a seasonal resting refuge for South American sea lions (Otaria flavescens). The regular presence of sea lions on the island is not only a touristic attraction in the region, but also a problem to the fishery community. This community faces economic impacts in its activities due to fish depredation caused by sea lions. Because of this issue, the perceptions and attitudes of different stakeholders from the region are important to be considered by managers, so that a realistic and decentralized action plan can be designed. The goal of this study was to analyze how different local stakeholders perceived the Wildlife Refuge of Ilha dos Lobos. Additionally, how these stakeholders differed from each other in terms of attitudes, knowledge and perceptions. In October 2011, January and March 2012, face-to-face interview surveys were conducted with fishermen and tourists, and drop-off questionnaires surveys with business, and tourism professional and teachers, in a total of 150 questionnaires, 30 for each group. The results indicated existence of differences across the five stakeholder groups. It was also suggested that non-direct stakeholders had a more favorable view of the Wildlife Refuge of Ilha dos Lobos and the sea lion, whereas direct stakeholder (the fishermen) saw it as an obstacle to their fisheries activities.     

Identifying anthropogenic sources of nitrogen oxide emissions from calculations of Lagrangian trajectories and the observational data from a tall tower in Siberia during the spring-summer period of 2007

The task of identifying climatically significant regional anthropogenic emissions and estimating their contribution to the variability of nitrogen oxides observed at a monitoring station is considered on the basis of NO and NO₂ surface concentrations measured at the Zotino background observation station (60°26′ N, 89°24′ E, Krasnoyarsk Territory). The approach used is based on an estimation of the conditional probability of polluted air arriving from individual regions by using the results of calculating backward Lagrangian trajectories in the lower troposphere. It is established that the contribution of air masses supplied from industrial regions in the south of the Krasnoyarsk Territory to episodes of high concentrations of nitrogen oxides (>0.7 ppb) is larger than the contribution from cities and towns located in the south of Western Siberia. The results indicate that anthropogenic sources of pollution substantially affect the balance of minor gases in the lower troposphere on a regional scale and that this factor must be taken into account when observational data from the Zotino background station are analyzed and interpreted.     

Newly discovered hydrothermal fields along the ultraslow-spreading Southwest Indian Ridge around 63°E

The ultraslow-spreading Southwest Indian Ridge(SWIR) to the east of the Melville fracture zone is characterized by very low melt supply and intensive tectonic activity. Due to its weak thermal budget and extremely slow spreading rate, the easternmost SWIR was considered to be devoid of hydrothermal activity until the discovery of the inactive Mt. Jourdanne hydrothermal field(27°51′S, 63°56′E) in 1998. During the COMRA DY115-20 cruise in2009, two additional hydrothermal fields(i.e., the Tiancheng(27°51′S, 63°55′E) and Tianzuo(27°57′S, 63°32′E)fields) were discovered. Further detailed investigations of these two hydrothermal sites were conducted by Chinese manned submersible Jiaolong in 2014–2015. The Tiancheng filed can be characterized as a lowtemperature(up to 13.2°C) diffuse flow hydrothermal field, and is hosted by fractured basalts with hydrothermal fauna widespread on the seafloor. The Tianzuo hydrothermal field is an inactive sulfide field, which is hosted by ultramafic rocks and controlled by detachment fault. The discovery of the three hydrothermal fields around Segment #11 which receives more melt than the regional average, provided evidence for local enhanced magmatism providing heat source to drive hydrothermal circulation. We further imply that hydrothermal activity and sulfide deposits may be rather promising along the easternmost SWIR.     

Spatial variations in the air turbidity factor above the European part of Russia under conditions of abnormal summer of 2010

We analyze spatial variations in the air turbidity factor T obtained from the interpolation of ground-based solar radiometry data within the territory (40°–70° N, 30°–60° E) in summer 2010. The abnormal heat and connected fires of summer 2010 changed the mean values of air turbidity and the character of its spatial variations. As a result, a “tongue” of increased values of the turbidity factor was observed in the south-to-north direction in July, and a closed region of anomalous high T was formed over the territory (48°–55° N, 37°–42° E) to the south of Moscow and partly covered the Moscow region in August. Such a pattern resulted from blockage preventing from ingress of air masses from the west and producing closed air circulation over the European Part of Russia (EPR).     

Volume transport and distribution of deep circulation at 165°W in the North Pacific

We conducted full-depth hydrographic observations between 8°50′ and 44°30′N at 165°W in 2003 and analyzed the data together with those from the World Ocean Circulation Experiment and the World Ocean Database, clarifying the water characteristics and deep circulation in the Central and Northeast Pacific Basins. The deep-water characteristics at depths greater than approximately 2000 dbar at 165°W differ among three regions demarcated by the Hawaiian Ridge at around 24°N and the Mendocino Fracture Zone at 37°N: the southern region (10–24°N), central region (24–37°N), and northern region (north of 37°N). Deep water at temperatures below 1.15 °C and depths greater than 4000 dbar is highly stratified in the southern region, weakly stratified in the central region, and largely uniform in the northern region. Among the three regions, near-bottom water immediately east of Clarion Passage in the southern region is coldest (θ<0.90 °C), most saline (S>34.70), highest in dissolved oxygen (O₂>4.2 ml l^?1), and lowest in silica (Si<135 μmol kg^?1). These characteristics of the deep water reflect transport of Lower Circumpolar Deep Water (LCDW) due to a branch current south of the Wake–Necker Ridge that is separated from the eastern branch current of the deep circulation immediately north of 10°N in the Central Pacific Basin. The branch current south of the Wake–Necker Ridge carries LCDW of θ<1.05 °C with a volume transport of 3.7 Sv (1 Sv=10⁶ m³ s^?1) into the Northeast Pacific Basin through Horizon and Clarion Passages, mainly through the latter (～3.1 Sv). A small amount of the LCDW flows northward at the western boundary of the Northeast Pacific Basin, joins the branch of deep circulation from the Main Gap of the Emperor Seamounts Chain, and forms an eastward current along the Mendocino Fracture Zone with volume transport of nearly 1 Sv. If this volume transport is typical, a major portion of the LCDW (～3 Sv) carried by the branch current south of the Wake–Necker and Hawaiian Ridges may spread in the southern part of the Northeast Pacific Basin. In the northern region at 165°W, silica maxima are found near the bottom and at 2200 dbar; the minimum between the double maxima occurs at a depth of approximately 4000 dbar (θ～1.15 °C). The geostrophic current north of 39°N in the upper deep layer between 1.15 and 2.2 °C, with reference to the 1.15 °C isotherm, has a westward volume transport of 1.6 Sv at 39–44°30′N, carrying silica-rich North Pacific Deep Water from the northeastern region of the Northeast Pacific Basin to the Northwest Pacific Basin.     

未来黄淮海地区夏玉米光温水资源适宜度及灾害风险演变特征

为探索未来气候变化对黄淮海地区农业气候资源和夏玉米气候适宜度及灾害的影响,以黄淮海地区1981—2021年56个农业气象观测站夏玉米生育期观测资料、84个气象站逐日气象要素观测资料及中尺度区域气候模式（Regional Climate Model Version 3,RegCM3）输出的未来气候情景（Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios A1B,IPCC SRES A1B）下黄淮海2022—2100年0.25°×0.25°共897个格点逐日气象资料为基础,分析未来黄淮海地区光温水等农业气候资源演变特征,建立黄淮海夏玉米生长发育气候适宜度模型及气候适宜度灾害指数模型,研究未来气候变化对黄淮海夏玉米气候适宜度的影响特征,预估夏玉米农业气象灾害发生风险及特点。结果表明：（1）2022—2100年黄淮海地区夏玉米生长季热量资源呈明显增加趋势,降水资源总体为微弱上升趋势且阶段性变化明显,光照资源变化趋势不明显。（2）2022—2100年夏玉米全生育期气候适宜度呈总体平稳略有下降波动趋势,并具有一定阶段特征和发育期差异。各生育期相比,播种出苗期气候适宜度相对最差,成熟期最好。（3）全生育期温度适宜度总体呈稳定波动下降趋势,说明未来气候明显变暖趋势对夏玉米生长总体不利;水分适宜度和光照适宜度总体稳定、变化趋势不明显,说明未来水分和光照资源对夏玉米的生长基本有利。（4）由各年代来看,2080年代、2090年代温度适宜度最差,2020年代最好;2030年代水分适宜度最差,2080年代最好;2080年代、2090年代光照适宜度明显偏差,2020年代、2030年代明显偏好。综合来看,2061—2100年期间夏玉米气候适宜度总体偏差,2020年代最好。（5）抽雄吐丝期遭受高温热害风险最大,三叶至七叶期发生旱涝风险最大,播种出苗期发生寡照（连阴雨）风险最大,而成熟期发生各种农业气象灾害风险均最小。（6）2080—2098年期间夏玉米拔节期、抽雄吐丝期、灌浆至乳熟期遭受高温热害的风险大;2031—2035年、2046—2056年播种出苗至拔节期发生阶段性严重旱涝灾害风险等级高。2030年代和2040年代及2026年、2080—2093年播种出苗期出现寡照（连阴雨）的风险较大。